Sound translating device



March 21, 1933. H, R, CLARKE sown TRANSLATING DEVICE Filed April 12, 1930 //vv/v 70/? h! P. CLARKE ATTO/PNE) Iii) known in the art.

Patented Mar. 21 1933 UNITED STATES PATENT OFFICE B. CLARKE, 0F NEWARK, NEW JERSEY, ASSIGNOR T0 BELL TELEPEONE LABO- ME'OBIES, INCOBYOBATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK SOUND TRANSLATING DEVICE Application filed April 12, 1930. Serial No. 443,721.

This invention relates to sound translating devices and more particularly to a unitary element for damping the mechanical motion of a vibratile member in such devices.

Damping devices comprising a plurality of loosely disposed leaves adjacent a. vibratile member in translating apparatus are Certain difiiculties, however, have been experienced in obtaining uniform cooperative action among the leaves and equally distributed damping effect over the desired area of the vibratile member. Further difli'culty has been experienced due to slipping or rotation of the leaves with respect to one another with a resultant loss in the transmission efiiciency of the translating apparatus.

An object of this invention therefore, is to improve the damping of the vibratile element in translating apparatus and increase the eficiency and dependability thereof.

In accordance with the .general features of the present invention an acoustic device such as a telephone transmitter is provided with a damping element comprising a plurality of thin leaves formed from flexible strips folded and interfolded with each other in such a manner that alternate leaves are connected together by hinges and the hinges;

.. arranged in helical formation and sufficient rigidity is present in the book to prevent any slipping or rotation of the individual leaves.

e damping book of this invention is 'preferably constructed of thin strips of paper or similar flexible material folded over and over each other in alternate relation to am a book or pile of the desired thickness.

Afterithe folding; a hole of a predetermined size and form is unched through the center of the book and t e corners of the leaves are I stamped or cut to the desired shape.

- A mdre complete under-minding of this invention will he had from the following detailed romeo to the accom anymg mg m y 1 is 1. cross-sectional g y of a telephone hand set having a, transdiap mitter embodying the damping element of this invention;

Fig. 2 shows the initial relation of two strips of paper in accordance with this invention from which the damping element shown in Fig. 1 is made;

Fig. 3 represents the expanded strips of paper folded at right angles to one'ana other, and

Fig. 4 shows in perspective the complete unitary damping element of this invention with the leaves extended to show the relative position of the hinges on adjacent leaves.

In a specific embodiment illustrated in Fig. 1 the invention is employed in the transmitter of a hand telephone comprising a handle 10, at one" end of which the transmittencasing 11 is mounted. An annular dish-shaped metallic member 12 is threaded 70 to the casinglO and supports a rigid annular bridge. piece 13 having a cylindrical central aperture partially closed at one-end by an inwardly extending annular flange 14 which forms a seat for an inverted metallic cup 15 75 containing a variable resistance material, such as comminuted carbon, 16. The open end of a chamber formed by the flange 1d and the inverted cup 15 is closed by thefliat central portion of a diaphragm 17 The diaphragm 17 has a marked natural period of vibration and when acted upon by sound waves of a" frequency atror near its natural period, will have a greater response thereby causing resonance peaks in the transmitted speech frequencies. This non-uniform response results in distortion of a signal to be reproduced. In order to ove'rcome this result and thereby obtain a substantially uniform response for the vibratory diaphragm over the range of frequencies it is desired to transmit, a dam ingelement 18 is interposed between the gm 17 and the annular. flange 14. The damping element 18 comprises a plurali of. leaves loosely connected together to allow free but limited axial displacement of the leaves and serves to close the gap between the carbon containing chamber-1nd the diaphragm 17 to prevent leakage ofthe carbon 1 and thereby impair the efiicient operation of the dam ing element. It is, therefore, de-

sirable t at the number of interstices into next preceding hinge and that the hinges which the carbon granules may filter be reduced'as much as sible with the necessa number of leaves in the book to provide s ficient dam ing. It is also desirable that the damping e ement should have suflicient rigidity to prevent rotative or sliding movement of t e leaves with respect to one'another. Therefore, the damping element of this invention is made of two slmilar strips of paper 19 and 20, 'or other flexible material, or of a single piece of paper having similar strip-like portions at right angles to one another. The two strips 19 and 20 are fastened together at 21 as shown in Fig. 2, and folded and interfolded with one another to form a book, the alternate leaves of which are hinged together at adjacent ed es. The hinges on adjacent leaves are at rig t angles to one another and rotated progressivel so that the hin es are in a substantially he 'cal formation, t at is, the hinges define the in-' terrupted or broken periphery of a spiral of a diameter equal to the diameter of the individual leaves.

The method of constructing the damping element may be understood more clearly wit reference to Fig. 3.. When the strips are interfolded, the leaf 22 of the strip 19-will rest A lponthe end leaf 21 and be hinged thereto on the edge 23; leaf 24 ofthe strip 20 will disposed adjacent the leaf 22 and will be attached to the leaf 21 by the hinge 25 which is at right an Ice to the 23. Similarly, the leaf 26 will be ad'a'cent the leaf 24 and will be attached to the eaf 22 bythe hinge 27 which is at right angles to'the hinge 25.- It will ,thus be seen that each hinge is advanced 90? in either a clockwiseor counter-clockwise direction with respect to the are arranged, therefore, in'a substantially helical formation, The corners of the leaves are cut or trimmed to the desired shape by any suitable means, such as a die in a press and a hole of therequired dimensions is punched" throu h the center of the leaves; In-a cific orm shown in Fig. 4 the com letedbook com rises a. plurality of inte olded iubstantia inges at rig this figure, the shaded leaves are formedannular leaves with successive ht angles to one another. In

' hin anules may filter are considerably reduced 1n number and the damping action of the element is improved. The progressive rotation of the hinges also increases the rigidity of the damping element so that the tendency for the leaves to rotate with respect to one another or slide over one another is eliminated.

Although in the foregoing the damping element of this invention is shown employed in a tele hone transmitter, it may also be employe in connection with any vibratile member, for example the diaphragm of a sound receiving device, to efficiently damp the mechanical motion thereof.

In the specific embodiment of the invention shown and discussed hereinbefore, two strips of paper or similar flexible material are shown folded and interfolded. It is to be understood, however, that any number of strips arran d at suitable angles to one another, may employed without departing from the scope of this invention as set forth in the appended claims.

What is claimed is: v

1. A damping element for vibrating devices comprisin a book of thin leaves, certain adjacent e ges of alternate leaves being connected together by integral hinges succes-- sively arranged in helical formation.

2. A damping element for vibratin devices comprising two interwoven sets 0 thin leaves hinged at alternate edges, the hinges of the two sets being at right angles to'one another.

3. A damping element for vibratin devices comprising a plurality of sets-of hinged rings interwoven with one another, the

hinges of said'rin being progressively arranged in helical ormation.

4. A damping element for sound translat- 1ng devices comprising a plurality of thin flexible annular leaves in axial alignment to form a book, alternate leaves being hinged together at adjacent edges, and the hin on adjacent leaves being disposed at ang es to one another. J

5. In a sound translating device, a vibratile member, and a damping element adjacent .Sllld' member, said element comprising a pluralit of interwoven axially ali ed thin flexi 1e leaves, certain adjacent ges of alternate leaves being hinged together, and the on adjacent leaves being disposed at a es to one another. witness whereof, I hereunto subscribe my name this 10th da of A ril, 1930.

4 RY CLARKE.

from the strip 20 and the unshaded leaves are formed'from the strip 19.

Since one free edge of each leaf, as is clearly shown in Fig. 4, is adjacent the hinge connecting the leaves on either side thereof, the available intersticesinto which 

